I’m reading Animals without Backbones, Volume 2, and every so often I read something that reminds me of our long, long chain of common descent. It’s an old book, about 60 years old, but that means it’s simple and readable. Sure, every so often I mark something to look up in a newer book. But it’s great casual reading.
For example, roundworms, such as earthworms, have developed hemoglobin to help them carry oxygen around their bodies. It’s just floating in their blood: they haven’t developed blood cells. But it’s there. Six hundred million years separate us, but we have hemoglobin, too, slightly different but recognizably a related molecule doing the same job, with random changes in the non-functional parts. Isn’t knowledge wonderful?
You can read more about roundworms here. Or you can read about out last common ancestor (European Molecular Biology Laboratory (2010, February 1). Last ancestor humans shared with worms had sophisticated brain, microRNAs show. ScienceDaily. Retrieved January 21, 2012, from http://www.sciencedaily.com /releases/2010/02/100201101905.htm).